If the preview page is blank or the query page returns no data, work through these checks in order. Each targets a specific failure point in the Logtail collection pipeline.
Troubleshooting overview
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Check whether the log file is being updated. Logtail only collects incremental data — if the file has no new writes, nothing is collected.
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Check the machine group heartbeat status.
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Check that a Logtail configuration exists.
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Check that the Logtail configuration is applied to the machine group.
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If none of the above issues apply, check collection error messages in the console.
Step 1: Verify that the log file is being updated
Logtail collects only incremental logs. If the file receives no new writes after the configuration is applied, nothing is collected.
Check whether new data is written to the log file:
# Linux: Watch for new lines appended to the log file
tail -f /path/to/your/logfile.log-
File is not being updated -- No new logs are generated. Confirm your application is writing to the expected path.
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File is being updated -- Proceed to Step 2.
Logtail does not collect historical logs by default. To import logs written before the configuration was applied, see Import historical logs from log files.
Step 2: Check the machine group heartbeat
Check the heartbeat status of your machine group in the Simple Log Service console. For details, see Manage machine groups.
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Heartbeat is FAIL -- The server is not communicating with Simple Log Service. How do I troubleshoot the errors that are related to Logtail machine groups?
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Heartbeat is OK -- Proceed to Step 3.
Step 3: Confirm that a Logtail configuration exists
If no Logtail configuration exists, create one. Manage Logtail configurations for log collection.
If a configuration already exists, verify:
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Log path matches the actual file location -- The configured log path must match the actual log file location on the server.
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One configuration per file -- By default, only one Logtail configuration can collect from a given log file. What do I do if I want to use multiple Logtail configurations to collect logs from a log file?
Step 4: Verify that the Logtail configuration is applied to the machine group
On the Machine Group Settings page, check that the Logtail configuration is applied to the target machine group.
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Not applied -- Apply it. Manage machine groups.
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Already applied -- Proceed to Step 5.
Step 5: Check collection errors
If the previous steps did not reveal the issue, inspect Logtail error messages and log files.
View error messages in the console
Check collection errors in the Simple Log Service console. For details, see How do I view Logtail collection errors?
Review Logtail log files
Logtail logs all WARNING and ERROR messages. Check the following files for details.
Host environment
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Operating system |
Logtail version |
Log file path |
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Linux |
64-bit |
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64-bit Windows |
64-bit |
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32-bit |
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|
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32-bit Windows |
32-bit |
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On Linux, /usr/local/ilogtail/logtail_plugin.LOG contains logs for plugin-based data sources such as HTTP, MySQL binlog, and MySQL query results.
On 64-bit Windows, both 32-bit and 64-bit applications can run. The operating system stores 32-bit applications in a separate x86 directory, which is why the log paths differ.
Container environment
For containerized Logtail, check these files inside the Logtail container:
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/usr/local/ilogtail/ilogtail.LOG -
/usr/local/ilogtail/logtail_plugin.LOG
Check usage limits
If you collect a large volume of log data or from many files, the default throughput may be insufficient. Adjust startup parameters to increase throughput. For details, see Configure the startup parameters of Logtail.
Submit a support ticket
If the issue persists, submit a ticket with the following details:
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Logtail configuration name and machine group name
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Machine group heartbeat status
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Relevant error messages from the collection error view or log files
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Log file path and a sample of the log content